The ultimate objective of the proposed research is to reduce cancer risk (incidence and mortality) in African-Americans. As compared to American Caucasians, the overall cancer risk is greater in African-Americans. Socioeconomic differences are one factor which may account for the difference in cancer risk between African-Americans and American Caucasians. In addition, the liver has been shown to play a critical role in carcinogen metabolism. Hepatic oxidative and acetylator phenotypes have been associated with an increased incidence of cancer (e.g. bladder, lung). No previous studies have assessed hepatic oxidative phenotypes in African- Americans, and only one study has assessed oxidative phenotypes in American Caucasians. Likewise, only one study has assessed acetylator phenotypes in both populations. In this cross-sectional study, 250 African-Americans and 250 American Caucasians will be recruited from the Memphis Health Department. Oxidative and acetylator phenotypes will be determined following oral administration of dextro-methorphan and caffeine. Urine will be collected and analyzed by HPLC for parent drug and metabolite, and hepatic metabolic phenotype determined. The socioeconomic status (indigent or non indigent) of each subject will be determined by the use of published socioeconomic indexes. Interracial and socioeconomic comparisons will be evaluated between the groups. Subsequent case-controlled studies are planned to determine the association of cancer in African-Americans and hepatic metabolic phenotype. The results of this pilot study will provide a control population to which concurrent controls from the planned case- control studies can be compared.